1. Field of the Invention
The present invention relates generally to medical methods and apparatus. More particularly, the present invention relates to methods and apparatus for closing large arterial penetrations such as those formed for cardiac access during interventional procedures.
Angioplasty, atherectomy, drug delivery, stenting, and a variety of other interventional radiological procedures have proven to be of great benefit in the treatment of coronary artery disease. Such procedures are routinely performed by entering the femoral artery in a patient's groin and advancing an interventional catheter through a guiding catheter, over the aortic arch, and into the coronary arteries. Access to the femoral artery in the groin is typically achieved with an access sheath having a working diameter in the range from 4 Fr to 16 Fr, where one French equals 0.33 mm.
After the interventional procedure has been completed, the interventional and guiding catheters are removed, leaving the access sheath in place. The access sheath maintains hemostasis for as long as it is in place, and removal of the access sheath will result in bleeding from the femoral artery through the vessel wall penetration into the tissue tract from which the access sheath has been removed. A variety of protocols have been developed for closing the arterial wall penetration and sealing the access tract. Most simply and reasonably effectively for smaller diameter access penetrations, pressure may be applied on the patient's skin above the tissue tract and vessel wall penetration for sufficient time to permit coagulation, typically from 10 minutes to 30 minutes. While effective for smaller vessel wall penetrations, the need to employ a surgical nurse or other trained personnel to maintain pressure on the tissue tract and vessel during coagulation is very inefficient.
To improve the efficiency and reliability of the vessel wall closure, other techniques have been proposed. For example, devices have been developed for delivering hemostatic plugs through the vascular access sheath in order to promote hemostasis. Such apparatus are commercially available under the tradename Angio-Seal™ from St. Jude Medical, Inc., St. Paul, Minn. Other devices for suturing the vessel wall penetration through the tissue tract are available under the tradename Perclose® ProGlide™ from Abbott Vascular Devices, a division of Abbott Laboratories, Chicago, Ill. While such suture-based devices have been used to close large vessel penetrations, suturing can cause puckering of the vessel wall which can lead to an undesirable reduction in lumen size of the vessel. A third approach which is particularly advantageous since it leaves no suture or implant in the patient is available under the tradename Boomerang® Wire from Cardiva Medical, Inc., Sunnyvale, Calif. The Boomerang® Wire device provides for a temporary hemostasis after removal of the access sheath by expanding a small disk on the luminal side of the femoral wall penetration to allow natural clotting to occur in the tissue above the penetration.
While each of these approaches can be an improvement over applying manual pressure to the access site, they have proven to be less effective with very large access tracts and vessel wall penetrations such as those used in percutaneous valve repair and replacement. Those recently developed procedures require very large access penetrations and sheaths, often from 10 Fr to 24 Fr, and usually require bilateral penetration with a smaller access tract formed into the contralateral femoral artery. Access and closure of such large vessel penetrations are generally accomplished surgically by cutting down to the vessel. Percutaneous access and closure protocols are not routinely performed at present.
For these reasons, it would be desirable to provide improved and alternative techniques and systems for closing larger diameter femoral access tracts and vessel wall penetrations. It would be particularly desirable to provide such techniques and systems which may be employed with bilateral access protocols having at least one large diameter femoral wall penetration. At least some of these objectives will be met by the inventions described below.
2. Description of the Background Art
Vascular closure devices are described in U.S. Pat. Nos. 6,190,857; 7,169,168; and 6,056,769. See also US2006/0200075 and U.S. Pat. No. 7,008,442.